Pneumatic gauging device



Nov. 6, 1951 MANOMETER DEFLEGTION, MM OF WATER Filed Feb. 16, 1950 CALIBRATION CURVE 2OO OF AIR JET GAGE I I I I l I 6O -4O 20 0 2O 4O 6O ANGULAR DIVERGENCE OF TEST PRISMS IN SECONDS INVENTORS DO/V 0. HENDR/X RUDOLPH M LANGER ATTORNEY Patented Nov. 6, 1 951 2,573,843 7 PNEUMATIC GAUGING DEVICE Don 0. Hendrix and Rudolph M. Langer, Pasa-' dena, Calif., assignors to the United States of America as represented by the Secretary of the Navy Application February 16, 1950, Serial No. 144,466

This application is a continuation-in-part of a copending application, Serial No. 785,742, filed November 13, 1947, now abandoned.

The present invention relates to gauging devices and more particularly to gauging devices for rapidly and accurately checking or comparing angles.

In the manufacture of articles having angles which must conform to high standards of accuracy and which may be manufactured in large scale production quantities to within less than a second of arc of an accepted standard, it becomes necessary to provide some means for rapidly and accurately gauging such angles to determine if they are within the permissible limits of error. An example of such an article is an optical prism.

A method of checking the accuracy of linear dimensions has been heretofore in use in industry employing fluid nozzles or orifices disposed in close proximity to the surface of a workpiece to be gauged and comparing its deviation from an accepted standard by measuring the fluid leakage between the workpiece and faces of the nozzles.

The present invention contemplates the use of fluid flow in the gauging of angles by comparing them with a master angle and has as one of its objects the provision of such a gauging device which will give a rapid, accurate, indication of any deviation from the master.

Another object of the present invention is to provide a fluid gauging device for angles by means of which device the exact amount of angular error, if any, may accurately be determined.

Another object of the invention is to provide a fluid gauge for angles wherein the angular divergence from an acceptable size standard is indicated by the pressure difierence between lines connected to a plurality of spaced nozzles connected in pairs and disposed in close proximity to the adjacent sides of an angle to be gauged.

Another object of the invention is to provide in such a fluid gauge for angles means for automatically compensating for fluctuations in fluid pressure or suction.

A further object of the invention is to provide an angle measuring device whose sensitivity can be regulated in accordance with the degree of error permitted.

Other objects and their attendant advantages will become apparent when the following detailed description is read in conjunction with the accompanying drawings wherein:

Fig. 1 is a diagrammatic viewof one embodi- 6 Claims. (Cl. 73-375) ment of the present invention with a workpiece shown in place; and

Fig. 2 is a representative graph by means of which the divergence of an angular surface on a workpiece from a desired angle may be determined from pressure readings obtained.

In the embodiment illustrated the numeral I0 designates the body of the gauge which may have converging sides H and [2 which include between their adjacent faces an angle l3 approximately the same as the angle of a workpiece to be gauged, such as the prism l5 shown. Adjustably mounted in the sides I! and 12 are nozzles IE, l1, l8, and i9 which are adapted to form fluid leakage paths with the adjacent sides II and [2 of the angle. The inner nozzles l6 and II are located, one on each face, close to the vertex M of the workpiece, the outer nozzles l8 and I9 being preferably as far from the vertex as the dimensions of the prism permit. The nozzles are slidable inwardly or outwardly for purposes to be later described and wing nuts 23 maybe provided for clamping the nozzles in place after they have been properly set. Any suitable means such as micrometer or differential screws may be employed to control the adjustment of the nozzles. Supporting means such as the spaced parallel bars 20' may be provided to support the angle in a spaced relationship with the sides of the gauge body I0 as shown. These bars may be in the form of knife edges so that a line contact is provided with the prism.

The nozzles are connected in pairs, the inner nozzles l6 and I! being connected in parallel by means of tubes 2| and 22 and the outer nozzles l8 and H) by tubes 23 and 24, each pair of tubes joining supply tubes 25 and 23 respectively. Air pressure or suction from a common source 33 may be applied through any suitable throttling means, such as the matched capillary tubes 21 .and 28, which will limit and equalize the flow of fluid to the pairs of nozzles. Each of the tubes 2|, 22, 23, and 24 are provided with valves 29, 30, 3 I, and 32 respectively for separately shutting off the fluid supplied to each nozzle.

Tubes 34 and 35 may connect the branch tubes 25 and 26 with a suitable pressure responsive device such as the opposite limbs 36 and 31 of a manometer 38. A scale 39 indicates the level of a fluid 40 in the manometer. The arrangement is such that the differential between the fluid levels indicates any variation in pressure in lines 34 and 35.

The operation of the apparatus is as follows:

i When the selected angle of a workpiece, such as the rism i5, is to be checked, 8. test prism hav; ing a known correct angle is first placed in the gauge and the nozzles are adjusted so that there is a clearance of about one thousandth of an inch between the faces of the workpiece angle and the orifices of each nozzle. This may be done in the embodiment illustrated by adjusting. the nozzles inwardly or outwardly. The nozzles are then balanced by turning off one nozzle of each pair, for example, by closing valves 29 and 32 antladjusting the clearance between the testworkpiece and the other two nozzles l1. and 18 until there is equal fluid leakage between the sides ofv the test prism and the nozzles as will be indicated by a zero reading on the manometer scale 39 The nozzles are then clamped in position by tightening their respective wing'nuts 20. Valves; 30 and 3| are now closed, the valves 29 and 32 opened, and the nozzles l6 and I9 adjusted" in the same way. With all four valves then opened, the reading on the manometer should: be close to zero, any final adjustment beingmade'by. changing one. of the nozzles: slightly.

The standard prism may now be removed. and a prism: to be tested may be substituted. therefor; If the angle of. the latter is correct the reading on themanoineter will not: change, but. if its angle is too small. therev will he a greater flow through the outer nozzles l 8 and i9 thanthrough the inner nozzles t6 and H thus creatinga difierenti'al pres.- sure in the branch tube 34'causingthe' liquid 40 to rise in one limb of the manometer 38. If the angle is too large. then. the. flow will be greater through the inner nozzles I6 and i1 and: the deflectionwilllbe in the opposite limbof. the manom'-- eten.

The angular. error can be. accurately determined by' first calibrating. the. gauge using. a given: constant pressure and a plurality t prisms whose angles differ f'rom; the. desired. angle by definite known amounts, as: would. be previously determinedby optical measurements or otherxsuitable' means.

By plotting a:- curve of manometer deflection: against angular divergence. a chart. having a. plot. such as line- H illustratedv in" Fig. 2-: can be! developed.

a typical manometer deflection that: might; be; caused. by a workpiece Whose angular errorisi to;

be determined. On the chart thispressure difT-- ferential may be indicated as 200. millimeter'sof water and the angular divergence can be de termined by referring to the plot M inFig. 2

and following the dotted line coordinates 43. In-

the problem given this error is found to be forty" seconds minus.

It should be noted here that the sensitivity of the gauge can be varied by regulating the'width .of the gap between the nozzles and-the sides ofi the workpiece. A smaller gap williincrease the sensitivity and'a large gap will-'decleasethe'sensitivity. Sensitivity canalso-beregulatedrby vary-- ing the fluid pressure or suction, the'zhigher the pressure or" suction the greater thesensitivity:

Hence if the tolerable errorisvery small; the sen- .sitivity' may be increased to detect exceedingly small angular variations from the acceptable standard.

An additional feature of? the; invention: lies i'n' It will be. apparent that with such a. chart the size or error of an unknown angle:-

the fact that, when the four nozzles have been balanced as hereinbefore described, should a prism, be slightly rotated or displaced during the measuring process, the sensitivity of the gauge will not be aifected since such rotation may decrease the clearance between the workpiece and the nozzle on one side, the clearance between the workpiece and the nozzle on the other side, will be proportionately increased thus having no efiect on the ultimate manometer reading. It will be apparent therefore that a minimum of time need be employed to mount the workpiece and accurately determine any angular error It should be understood that many variations and modifications of the above-described invention may be resorted to without departing from the scope or spirit of the appended claims.

What is claimed is:

1. An angle gauging device for rapid measurement of angular surfaces on a workpiece com prising; a workpiece support, a pair of fluid nozzles. positioned: relative to said support so as to form fluid leakage paths with adjacent sides of an angle near its vertex, a second pair of fluid nozzles positioned relative to said support'so as to.- form: fluid leakage paths with the adjacent sides of an angle at points spaced from its vertex, means ior providing fluid flow through all of the nozzles, and. pressure indicating meansconnected to both pairs of nozzles, whereby variations insize betweenv angles successively gauged cause changes ii'rpressure at the nozzles which show on the. pressure indicating means.

2.1m anglegauging device for determining quickly the accuracy of a number or" like angular surfaces" comprising; a body having converging. sides the faces of which include an angle approximately the angle to be'gauged, a pairof'fluid nozzles positioned-inthe sides of the body so that each nozzle lies in close proximity to a surface to be measured and will form a fluid leakage gauged} means for supporting an angle to be gauged in-spaced relationship with the sides of the body, a pair. offluid' nozzles positioned inthe sides of the body so that each nozzle will form a fluid leakage path near'the vertex of adjacentsides. of an" angle, a secondpair oi fluid nozzles positioned in the sides of the body sothat each nozzle'with form a fiuidleakage path of a spaced distance from the vertex of the adjacent sides of. an angle, means for supplying. equal fluid flow to.- bothi'pairs of nozzles, and pressure responsive means interconnecting the pairs of nozzles, changes in thep'ressure'responsive means indicatingzvariationsi'in size between angles successively: gaugedi 4. An angle gauging device comprising; a body havin'giconverging sides; meansfor' supportingan angle: in spacedinterfitting relationship with sidesiofzaibodmapair offluid nozzles in thebod'y positioned to form fluid leakagepaths with the adjacent sides of an angleiat its -vertex. a second pair of fluid nozzles in the body positioned to form fluid leakage paths with the adjacent sides of an angle at a spaced distance from its vertex, means for adjusting the nozzles in approachment to and separation from the sides of the angle, means for supplying equal fluid flow to both pairs of nozzles, and pressure responsive means interconnecting the pairs of nozzles, changes in the reading of the pressure responsive means indicating variations in size between angles successively gauged.

5. An angle gauging device comprising; a body having converging sides, means for supporting an angle in spaced relationship with the body, balanced fluid supply means extending to said body and having two branch passages, a pair of nozzles in the body each forming fluid leakage paths with the adjacent sides of an angle at its vertex and connected in parallel with one of said branch passages, a second pair of fluid nozzles in the body forming fluid leakage paths with the adjacent sides of an angle at a spaced distance from its vertex and connected in parallel with one of said branch passages, a second pair of fluid nozzles in the body forming fluid leakage paths with the adjacent sides of an angle at a spaced distance from its vertex and connected in parallel with the other of said branch passages, and pressure responsive means interconnecting the pairs of nozzles, changes in the pressure responsive means indicating variations in size between angles successively gauged.

6. A gauging apparatus for comparing the sizes of unkown angles with known angles comprising; a body having converging sides, means for supporting an angle in spaced relationship with the body, balanced fluid supply means having two branch passages extending to said body, a pair of fluid nozzles disposed in the body each adapted to form fluid leakage paths with the adjacent sides of an angle at its vertex and connected in parallel with one of said branch passages, a second pair of fluid nozzles in the body each forming fluid leakage paths with the adjacent sides of an angle at a spaced distance from its vertex and connected in parallel with the other of said branch passages, pressure responsive means connected between each pair of nozzles for indicating difference in pressure therebetween, means for adjusting said nozzles towards and from a comparison angle of known size to balance the pressure in each pair of nozzles so that when an angle of unknown size is substituted for the comparison angle a change in the pressure responsive means will indicate angular variation from the angle of known size.

' DON O. HENDRIX.

RUDOLPH M. LANGER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,019,066 Balsiger Oct. 29, 1935 2,490,376 Rupley Dec. 6, 1949 

